JP6988647B2 - Polyester resin, primer composition, aqueous solution, base film with primer layer and prism sheet - Google Patents

Description

The present invention relates to a polyester resin, and more particularly, a polyester resin for forming a primer layer on a base film, a primer composition containing the polyester resin, and an aqueous solution using the primer composition. It relates to a liquid, a base film with a primer layer, and a prism sheet.

Conventionally, synthetic resins have been widely used as resins for various base materials because they have excellent properties such as dimensional stability, mechanical properties, heat resistance, transparency, electrical properties, and chemical resistance. For example, polyester films are used in various industrial fields such as packaging materials, magnetic cards, and printing materials. As the polyester film, a thermoplastic polyester such as polyethylene terephthalate (PET) or a copolymer thereof mixed with other resins as necessary is melt-extruded, molded, biaxially stretched, and heated. A fixed one is used. While such a polyester film has excellent physical properties, its surface is highly crystallinely oriented, so that when a coating layer is provided on the polyester film, there is a problem that the adhesion to the coating layer is poor. there were.

Therefore, in order to improve the adhesion between the polyester film and the coating layer, studies have been made to impart adhesion to the film surface. For example, the film surface may be easily adhered, or a primer layer made of various resins may be used. The method of providing it is known.
However, in recent years, the composition of the coating agent or the like forming the coating layer has been diversified, and depending on the type, the adhesion between the primer layer and the coating layer may not be sufficient, and further improvement of the adhesion is required. ..

For example, there is a prism layer as one of the coating layers. As a method for forming the prism layer, for example, an active energy ray-curable resin composition is introduced into a prism type, and the active energy ray is irradiated with the active energy ray-curable resin composition sandwiched between the prism type and the polyester film. Then, a method of forming a prism layer formed by curing the active energy ray-curable resin composition on the polyester film by curing the resin composition and removing the prism type can be mentioned. In the case of such a method, it is necessary to use a solvent-free active energy ray-curable resin in order for the prism pattern to be finely formed. However, the solvent-free resin has a lower penetration and swelling effect into the primer layer laminated on the polyester film than the solvent-based resin, and the active energy ray-curable resin composition is cured. Adhesion with the primer layer tends to be insufficient.

Therefore, Patent Document 1 has a coating layer formed on at least one side of a film, which is a composite resin composed of a resin containing a (meth) acryloyl group and a urethane resin, and a coating liquid containing a cross-linking agent. A characteristic laminated film is disclosed, and according to the technique, it is said to have excellent adhesion to a solvent-free active energy ray-curable resin used for forming a prism layer.

Japanese Unexamined Patent Publication No. 2016-64517

However, in recent years, the composition of the solvent-free active energy ray-curable resin used for forming the prism layer has been diversified, and the adhesion is not always sufficient even in the primer composition and the like proposed in Patent Document 1 above. ing.

Further, in a polyester film with a primer layer, it is common to remelt and recycle film scraps generated by slits and the like, but when a urethane resin is used as described in Patent Document 1 above, it is remelted and recycled. There is a concern that the recycled film may cause yellowing due to urethane resin, agglomerated foreign matter, etc., which may impair the quality.

Therefore, the present invention provides adhesion to both the base film and the coating layer, particularly the polyester film and the prism layer obtained by curing the solvent-free active energy ray-curable resin composition under such a background. It is an object of the present invention to provide a primer composition containing no urethane resin and a polyester-based resin for forming the primer composition for forming an excellent primer layer.

As a result of intensive studies in view of such circumstances, the present inventor has a carboxyl group in the side chain of the main chain, and has a specific structure in either the side chain of the main chain or at least one of the molecular ends of the main chain. By using the polyester resin, a primer composition that forms a primer layer having excellent adhesion to both the base film and the coating layer, particularly the prism layer obtained by curing the solvent-free active energy ray-curable resin composition. The present invention was completed by finding that a product can be obtained.

That is, the present invention is characterized by the following <1> to <14>.
<1> The side chain of the main chain has a carboxyl group, and at least one of the side chain of the main chain and at least one of the molecular ends of the main chain has a structure represented by the following formula (1). Characterized polyester resin.

(In the formula (1), R represents an alkylene group having 1 to 5 carbon atoms, X represents a hydrogen atom, an aryl group, an alkyl group having 1 to 5 carbon atoms, or a (meth) acryloyl group, and n represents 1 to 1. Indicates an integer of 20.)
<2> The polyester resin according to <1>, wherein X is a (meth) acryloyl group in the above formula (1).
<3> The polyester resin according to <1> or <2>, wherein the content of the structure represented by the formula (1) is 1 to 30% by mass.
<4> The polyester resin according to any one of <1> to <3>, which has an acid value of 1.5 to 150 mgKOH / g.
<5> The polyester resin according to any one of <1> to <4>, wherein the weight average molecular weight is 5,000 to 100,000.
<6> An aqueous liquid comprising the polyester resin according to any one of <1> to <5> dissolved or dispersed in an aqueous solvent.
<7> A primer composition comprising the polyester resin according to any one of <1> to <5>.
<8> The primer composition according to <7>, which further contains a cross-linking agent.
<9> The primer composition according to <8>, wherein the cross-linking agent is at least one compound selected from the group consisting of an isocyanate-based compound and a carbodiimide-based compound.
<10> In <8> or <9>, the content ratio of the polyester resin to the cross-linking agent is 99/1 to 30/70 as the mass of the polyester resin / the mass of the cross-linking agent. The primer composition described.
<11> An aqueous liquid comprising the primer composition according to any one of <7> to <10> dissolved or dispersed in an aqueous solvent.
<12> A base film with a primer layer, which comprises a primer layer composed of the primer composition according to any one of <7> to <10> on the base film.
<13> A prism sheet comprising a prism layer on the primer layer of the substrate film with the primer layer according to <12>.
<14> The prism sheet according to <13>, wherein the prism layer is a cured product of a solvent-free active energy ray-curable resin composition.

The primer composition containing the polyester resin of the present invention has excellent adhesion to both the base film and the coating layer, and is particularly solvent-free activity used for forming a polyester film and, for example, a prism layer. The energy ray-curable resin composition has excellent adhesion to the cured layer.
Therefore, the primer composition can be suitably used as a primer for providing a coating layer, particularly a prism layer, on a polyester resin base material such as a polyester film.

Hereinafter, the present invention will be described in detail, but these are examples of desirable embodiments.
In the present invention, the "(meth) acryloyl group" means an acryloyl group or a methacryloyl group, and the "(meth) acrylate" means an acrylate or a methacrylate.
Further, in the present invention, the term "carboxylic acid" includes a carboxylate, a carboxylic acid anhydride, a carboxylic acid halide, a carboxylic acid ester and the like.
Further, in the present invention, the "sheet" conceptually includes a sheet, a film, and a tape.

[Polyester resin]
The polyester resin of the present invention has a carboxyl group in the side chain of the main chain, and is represented by the following formula (1) at at least one of the side chain of the main chain and at least one of the molecular ends of the main chain. It is characterized by having a structure (hereinafter, may be referred to as "structure (1)").

In formula (1), R represents an alkylene group having 1 to 5 carbon atoms.
The alkylene group having 1 to 5 carbon atoms may be either linear or branched, and the linear group may be, for example, a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group or the like. Examples of the branched chain-like group include a propylene group, a 1-ethylethylene group, a 2-ethylethylene group, a 1,2-dimethylethylene group, a 1,1-dimethylethylene group, and 2,2. -The dimethylethylene group and the like can be mentioned.

When the polyester resin of the present invention is used in a primer composition for forming a primer layer provided between a base film and a coating layer, R has a carbon number of carbon atoms from the viewpoint of adhesion between the base film and the coating layer. It is preferably a linear alkylene group of 1 to 5. When R is linear, the wettability of the coating agent forming the coating layer with respect to the primer layer is improved, and as a result, the adhesion between the base film and the coating layer can be improved.
As R, a linear alkylene group having 1 to 4 carbon atoms is more preferable, and an ethylene group is further preferable.

In formula (1), X represents a hydrogen atom, an aryl group, an alkyl group having 1 to 5 carbon atoms, or a (meth) acryloyl group.
Examples of the aryl group include a phenyl group, an α-naphthyl group, a β-naphthyl group, an anthryl group, a phenanthryl group, a biphenyl group and the like.
Examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group and a 1-methylbutyl group. Examples thereof include 2-methylbutyl group, 3-methylbutyl group, 1,1-dimethylpropyl group, 1,2-dimethylpropyl group, 2,2-dimethylpropyl group, among which methyl group, ethyl group and isopropyl group. A tert-butyl group is preferable, and a methyl group is more preferable.

As described above, the polyester-based resin of the present invention can be preferably used by being contained in the primer composition, wherein a carbon-carbon double bond is contained in the compound forming the coating layer. May be. In that case, X is preferably a (meth) acryloyl group, which is an unsaturated group having high reactivity with the carbon-carbon double bond, and more preferably an acryloyl group.

In equation (1), n represents an integer of 1 to 20. If n becomes too large, the blocking resistance of the base film with a primer layer tends to decrease, so n is 20 or less, preferably 15 or less. Further, in order to improve the wettability of the coating agent forming the coating layer with respect to the primer layer and improve the adhesion between the base film and the coating layer, n is preferably 3 or more, and more preferably 4 or more.

As a preferable specific example of the structure (1), for example, the following can be mentioned.

The polyester-based resin of the present invention forms a cross-linked structure by reacting with a cross-linking agent described later, but in this cross-linked structure, the molecular motility of the polyester structure portion of the polyester-based resin is limited. On the other hand, the structure (1) of the polyester resin present at at least one of the side chain of the main chain and at least one of the molecular ends of the main chain has a relatively high degree of steric and spatial freedom. Therefore, for example, when the polyester resin of the present invention is contained in the primer composition and used, the polyester resin of the present invention tends to segregate on the surface of the primer layer.

In such a case, since the structure (1) is hydrophilic, it is considered that the wettability of the coating agent forming the coating layer to the primer layer becomes large, and the adhesion between the primer layer and the coating layer becomes high.

The content of the polyester resin structure (1) of the present invention is preferably 1 to 30% by mass, and particularly preferably 3 to 15% by mass. If the content is too small, sufficient adhesion tends not to be obtained, and if it is too large, the blocking resistance of the base film with a primer layer tends to decrease.

The acid value of the polyester resin of the present invention is preferably 1.5 to 150 mgKOH / g, particularly preferably 4 to 100 mgKOH / g, particularly preferably 10 to 70 mgKOH / g, and further preferably 15 to 40 mgKOH / g. If the acid value is too low, it tends to be difficult to disperse water, and the adhesion and moisture heat resistance tend to decrease due to insufficient cross-linking with a cross-linking agent. On the other hand, if the acid value is too high, the water resistance tends to decrease.

The acid value in the present invention is due to the content of the carboxyl group in the polyester resin. Further, the carboxyl group referred to in the present invention also includes those in a carboxylate ion state in which the carboxyl group is neutralized with a basic compound. The acid value is determined by neutralization titration based on JIS K0070.

The weight average molecular weight of the polyester resin of the present invention is preferably 5,000 to 100,000, particularly 6,000 to 50,000, particularly 8,000 to 40,000, and further 13,000 to 30. 000 is preferable. If the weight average molecular weight is too low, the adhesion and moisture heat resistance tend to decrease, and if the weight average molecular weight is too high, the adhesion and water dispersibility tend to decrease.

The weight average molecular weight is a weight average molecular weight converted to standard polystyrene molecular weight, and is subjected to high performance liquid chromatography (manufactured by Tosoh Corporation, “HLC-8320GPC”), column: TSKgel SuperMultipore HZ-M (exclusion limit molecular weight: 2 × 10). ^6. Theoretical plate number: 16,000 stages / piece, filler material: styrene-divinylbenzene copolymer, filler particle size: 4 μm), measured by using two series.

The polyester-based resin of the present invention comprises, for example, a polyester-based resin having an acid anhydride structure at at least one molecular terminal of the main chain, and a compound having a functional group and a structure (1) capable of reacting with the acid anhydride. It can be obtained by reacting.

Hereinafter, the method for producing the polyester resin of the present invention will be described when X in the structure (1) in the polyester resin of the present invention has an unsaturated group.
As described above, when the polyester resin of the present invention is used in the primer composition and the coating layer bonded by the primer composition contains a carbon-carbon double bond, the polyester resin of the present invention is used. It is preferable to have an unsaturated group having a high reactivity with the carbon-carbon double bond.

Such a polyester-based resin may be described as, for example, a polyester-based resin (A) having an acid anhydride structure at the molecular end of at least one of the main chains (hereinafter, may be referred to as "polyester-based resin (A)"). And an unsaturated group-containing compound (B) having a functional group capable of reacting with an acid anhydride (hereinafter, may be referred to as “unsaturated group-containing compound (B)”). Can be done.

<Polyester resin (A) having an acid anhydride structure at the end of at least one of the main chains>
The polyester resin (A) can be obtained by copolymerizing the polyvalent carboxylic acid component (a1) and the polyol component (a2).

[Multivalent carboxylic acid component (a1)]
The polyvalent carboxylic acid component (a1) may be a polyvalent carboxylic acid having a divalent value or higher, and preferably contains at least a divalent carboxylic acid.

Examples of the divalent carboxylic acid include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, benzylmalonic acid, diphenylic acid, 4,4'-oxydibenzoic acid, naphthalenedicarboxylic acid and dimethylsodium 5-sulfoisophthalate;
Malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, itaconic acid, thiodipropionic acid , An aliphatic dicarboxylic acid such as diglycolic acid;
Alicyclic group of 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2,5-norbornandicarboxylic acid, adamantandicarboxylic acid and the like. Dicarboxylic acid;
And so on.
These may be used alone or in combination of two or more.

Among these, at least one of aromatic dicarboxylic acid and alicyclic dicarboxylic acid is mainly used in terms of adhesion of the primer layer to the coating layer and stability of the aqueous liquid when dissolved or dispersed in an aqueous solvent. It is preferable to use it as a component, and it is preferable to use an aromatic dicarboxylic acid as a main component, and further preferably isophthalic acid as a main component, from the viewpoint of excellent adhesion.

Here, the main component means that the polyvalent carboxylic acid component (a1) is usually contained in an amount of 50 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more, based on the whole polyvalent carboxylic acid component (a1).

The content ratio of the divalent carboxylic acid is preferably 70 to 97 mol%, particularly 80 to 97 mol%, and further 85 to 96 mol%, particularly, with respect to the whole polyvalent carboxylic acid component (a1). It is preferably 90 to 95 mol%. If the content ratio is too low, the moisture and heat resistance tends to decrease or gelation tends to occur during the manufacturing process, and if the content ratio is too high, water dispersion tends to be difficult.

In the present embodiment, a trivalent or higher polyvalent carboxylic acid can be used for the purpose of increasing branching points in the polyester resin (A). Examples of the trivalent or higher polyvalent carboxylic acid include trimellitic acid, pyromellitic acid, adamantane tricarboxylic acid, and trimesic acid.

In the present embodiment, the polyester-based resin (A) reacts with the reaction site of the unsaturated group-containing compound (B), preferably the (meth) acrylate-based compound, and the cross-linking agent described later in the polyester-based resin (A). A carboxylic acid anhydride having two or more carboxylic acid anhydride structures as a polyvalent carboxylic acid component (a1) in that it has a function of forming a point, a function as a chain extender, and a function as a hydrophilicity-imparting agent. (A11) (hereinafter, may be referred to as "carboxylic acid anhydride (a11)") is preferably contained.

The carboxylic acid anhydride (a11) may have at least two carboxylic acid anhydride structures.

Specific examples of the carboxylic acid anhydride (a11) include, for example,
1,2,4,5-benzenetetracarboxylic acid dianhydride (pyromellitic acid anhydride), 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride, 4,4-oxydiphthalic acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, ethylene glycol bistrimethylate dianhydride, 2,2', 3,3' Aromatic carboxylic acid anhydrides such as −diphenyltetracarboxylic acid dianhydride, 2,2 ′, 3,3 ′-diphenylsulfone tetracarboxylic acid anhydride, thiophene-2,3,4,5-tetracarboxylic acid dianhydride object;
1,2,3,4-Cyclobutanetetracarboxylic acid dianhydride, 5- (2,5 dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, 5- (2,2) 5-Dioxotetrahydrofuryl) -3-cyclohexene-1,2-dicarboxylic acid anhydride, cyclopentanetetracarboxylic acid dianhydride and other alicyclic carboxylic acid anhydrides;
An aliphatic carboxylic acid anhydride such as ethylenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-pentanetetracarboxylic dianhydride;
And so on.
These can be used alone or in combination of two or more.

Among these, tetracarboxylic acid dianhydride is preferable because it does not easily cause gelation during resin production, and aromatic tetracarboxylic acid dianhydride is preferable from the viewpoint of adhesion between the coating layer and the primer layer. 1,2,4,5-benzenetetracarboxylic acid dianhydride (pyromellitic anhydride) is preferred.

The content ratio of the carboxylic acid anhydride (a11) in the polyvalent carboxylic acid component (a1) is preferably 2 to 30 mol%, particularly 3 to 20 with respect to the entire polyvalent carboxylic acid component (a1). It is preferably mol%, more preferably 4 to 15 mol%, particularly 5 to 10 mol%. If the content ratio is too low, it becomes difficult to disperse the produced polyester resin in an aqueous solvent, or the cross-linking point with the cross-linking agent is insufficient, and the adhesion and the heat resistance to moisture and humidity are lowered. Tend. If the content ratio is too high, gelation occurs during the manufacturing process, the hydrophilicity becomes high, so that the moist heat resistance is lowered, the molecular weight is difficult to increase, and the adhesion with the coating layer is lowered, or when the cross-linking agent is blended. Since the crosslink density becomes too high, the adhesion to the coating layer tends to decrease.

[Polyform component (a2)]
Examples of the polyol component (a2) include an aliphatic diol having a linear structure, other dihydric alcohols, and trihydric or higher polyhydric alcohols.

Examples of the aliphatic diol having a linear structure include ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1, , 9-Nonandiol, 1,10-decanediol, 1,12-dodecanediol, polyethylene glycol, polytetramethylene glycol and the like.

Examples of other dihydric alcohols include propylene glycol, dipropylene glycol, 2,4-dimethyl-2-ethylhexane-1,3-diol, 2-methyl-1,3-propanediol, and 2,2-dimethyl. -1,3-Propylene diol (neopentyl glycol), 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 1,3-butanediol, An aliphatic diol having a branched structure such as 3-methyl-1,5-pentanediol and 2,2,4-trimethyl-1,6-hexanediol;
1,2-Cyclohexanedimethanol, 1,3-Cyclohexanedimethanol, 1,4-Cyclohexanedimethanol, Spiroglycol, Tricyclodecanedimethanol, Adamantanediol, 2,2,4,4-Tetramethyl-1,3 -Alicyclic diols such as cyclobutanediol;
4,4'-thiodiphenol, 4,4'-methylenediphenol, bisphenol S, bisphenol A, bisphenol fluorene, 4,4'-dihydroxybiphenyl, o-, m- and p-dihydroxybenzene, 2,5- Aromatic diols such as naphthalene diol and p-xylene diol;
And these ethylene oxide and propylene oxide adducts;
And so on.

Examples of the trihydric or higher polyhydric alcohol include pentaerythritol, dipentaerythritol, tripentaerythritol, glycerin, trimethylolpropane, trimethylolethane, 1,3,6-hexanetriol, and adamantanetriol.

Among these, it is preferable to use an aliphatic diol having a linear structure in terms of adhesion between the coating layer and the primer layer, and ethylene glycol is excluded in that it has appropriate flexibility and excellent adhesion. It is preferable to use an aliphatic diol having a linear structure, and it is particularly preferable to use diethylene glycol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol, and in particular, resin crystals. It is preferable to use diethylene glycol because the degree of conversion is reduced and the adhesion is more excellent.

Further, from the viewpoint of stability of the aqueous liquid when dissolved or dispersed in an aqueous solvent, it is preferable to use an aliphatic diol having a linear structure in combination with other polyol components, and further, a coating layer and a primer layer. From the viewpoint of adhesion, it is preferable to use an aliphatic diol having a linear structure and an aliphatic polyol having a branched structure in combination, and in particular, neopentyl glycol, 2-methyl-1,2, as the aliphatic polyol having a branched structure. 3-Propanediol and butylethylpropanediol are preferably used, and neopentyl glycol is particularly preferable.

When a linear structure aliphatic diol and other polyol components are used in combination, the usage ratio (molar ratio) of the linear structure aliphatic diol and other polyol components is the linear structure aliphatic diol / other than that. As the polyol component of, 98/2 to 50/50 is preferable, 95/5 to 60/40 is more preferable, and 90/10 to 70/30 is particularly preferable.
If the amount of the polyol component other than the aliphatic diol having a linear structure is too large, the adhesion tends to decrease, and if it is too small, the stability of the aqueous liquid tends to decrease.

[Manufacturing method of polyester resin (A)]
The polyester-based resin (A) can be obtained by copolymerizing a copolymerization component containing the polyvalent carboxylic acid component (a1) and the polyol component (a2), and for example, many excluding the carboxylic acid anhydride (a11). It can be produced by a method of reacting a hydroxyl group-containing prepolymer obtained by copolymerizing a valent carboxylic acid component (a1) and a polyol component (a2) with a carboxylic acid anhydride (a11).

First, a predetermined amount of the polyvalent carboxylic acid component (a1) and the polyol component (a2) excluding the carboxylic acid anhydride (a11) are mixed without a solvent. At this time, the mixing ratio (molar ratio) of the polyvalent carboxylic acid component (a1) excluding the carboxylic acid anhydride (a11) and the polyol component (a2) is the polyol with respect to 1 mol of the polyvalent carboxylic acid component (a1). The component (a2) is preferably 1.02 to 1.3 mol, more preferably 1.03 to 1.2 mol, and particularly preferably 1.04 to 1.1 mol.

This mixture is charged in an appropriate reactor and usually heated to 170 to 270 ° C. to promote an esterification reaction or a transesterification reaction while distilling off water or methanol as a by-product, and carrying out a hydroxyl group-containing pre. Produces a polymer.

Further, a polyester resin (A) having an acid anhydride structure at at least one molecular terminal of the main chain can be obtained by a ring-opening addition reaction using a carboxylic acid anhydride (a11) on the hydroxyl group-containing prepolymer. can.

When the carboxylic acid anhydride (a11) is reacted with the hydroxyl group-containing prepolymer, [1] the molar ratio of the hydroxyl group of the hydroxyl group-containing prepolymer to the carboxylic acid anhydride (a11) (molar of the carboxylic acid anhydride (a11)). When the number / number of moles of the hydroxyl group) is 1 or more, the carboxylic acid anhydride (a11) reacts with the terminal of the hydroxyl group-containing prepolymer, and the hydroxyl group-containing prepolymer has an acid anhydride structure at the end. Become.

[2] Even if the molar ratio is greater than 0 and less than 1, the molar ratio of the hydroxyl group of the hydroxyl group-containing prepolymer to the acid anhydride group of the carboxylic acid anhydride (a11) (the number of moles of the acid anhydride group / the said). When the number of moles of the hydroxyl group) is larger than 1, the hydroxyl group-containing prepolymer has an anhydride structure at its terminal while the chain is extended.
In the present embodiment, in the case of the above [2], the weight average molecular weight of the polyester resin of the present embodiment tends to be in the above-mentioned preferable range, and the adhesion between the coating layer and the primer layer tends to be higher. ,preferable.

Further, when the carboxylic acid anhydride (a11) is reacted with the hydroxyl group-containing prepolymer, it is usually reacted at 230 ° C. or lower, preferably 150 to 210 ° C., particularly preferably 160 to 190 ° C. when no catalyst is used. When a catalyst is used, the reaction can be carried out at room temperature to 100 ° C., preferably 40 to 90 ° C.

The catalyst is not particularly limited, but an amine-based catalyst is preferable, and triethylamine is particularly preferable because it easily volatilizes in the drying process.

Further, an esterification catalyst, a transesterification catalyst, another polymerization catalyst and the like can be appropriately blended, and for example, tetrabutoxytitanium can be used as the esterification catalyst. Moreover, various additives such as other stabilizers may be used.

A solvent is not always required for the above reaction, but if the viscosity of the reactant at the above temperature is too high, an appropriate solvent can be appropriately used to facilitate stirring.

Examples of such a solvent include ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, aromatic solvents such as benzene, toluene, xylene, mesitylene and pseudocumene, and amide solvents such as dimethylformamide and dimethylacetamide. .. It is preferable not to use a solvent that may react with the polyester resin, such as an ester solvent and an alcohol solvent.
Thus, the polyester resin (A) can be obtained by the above-mentioned method.

The polyester resin (A) needs to have a carboxyl group in the side chain of the main chain, and the carboxyl group is preferably derived from a carboxylic acid anhydride (a11), preferably pyromellitic acid. ..

<Unsaturated group-containing compound (B) having a functional group capable of reacting with acid anhydride>
The unsaturated group-containing compound (B) has a functional group capable of reacting with acid anhydride. The unsaturated group-containing compound (B) may be a monofunctional compound containing one unsaturated group in the molecule or a polyfunctional compound containing two or more unsaturated groups in the molecule. In particular, in the present embodiment, the unsaturated group-containing compound (B) is preferably a (meth) acryloyl group-containing compound in terms of adhesion to the coating layer.

As the functional group capable of reacting with the acid anhydride, conventionally known functional groups can be used, and examples thereof include a hydroxyl group, an amino group, a mercapto group, an epoxy group and the like. Of these, hydroxyl groups and epoxy groups are preferable from the viewpoint of hue and odor, and hydroxyl groups are particularly preferable from the viewpoint of reactivity.

As the monofunctional compound, a monofunctional (meth) acrylate is preferable. Examples of the monofunctional (meth) acrylate include polyalkylene glycol mono (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxy. Butyl (meth) acrylate, ethylene glycol-propylene glycol block copolymer mono (meth) acrylate, ethylene glycol-tetramethylene glycol copolymer mono (meth) acrylate, caprolactone modified mono (meth) acrylate, glycidyl (meth) acrylate, 4-hydroxy Examples thereof include butyl (meth) acrylate glycidyl ether.

As the polyfunctional compound, polyfunctional (meth) acrylate is preferable. Examples of the polyfunctional (meth) acrylate include trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, and dipentaerythritol penta (meth) acrylate. In addition, polybutadiene containing both terminal hydroxyl groups, a polymer having a functional group capable of reacting with a terminal unsaturated group and an acid anhydride group, an oligomer, and the like can be mentioned.

Among these, as the unsaturated group-containing compound (B), those having a (meth) acryloyl group are preferable from the viewpoint of adhesion between the coating layer and the primer layer, and in particular, a (meth) acryloyl group and a polyoxyalkylene group. It is preferable to have an acryloyl group and a polyoxyalkylene group, and a polyalkylene glycol monoacrylate is more preferable.

Examples of the polyalkylene glycol monoacrylate include polyethylene glycol monoacrylate, polypropylene glycol monoacrylate, and polybutylene glycol monoacrylate, which have a primary hydroxyl group from the viewpoint of reactivity with an acid anhydride group (polyethylene). Glycol monoacrylate, polybutylene glycol monoacrylate) is preferable, and polyethylene glycol monoacrylate is more preferable from the viewpoint of adhesion between the coating layer and the primer layer.

<Method for producing polyester resin in which X has an unsaturated group in the structure (1)>
As described above, the polyester-based resin in which X in the structure (1) has an unsaturated group can be obtained, for example, by reacting the polyester-based resin (A) with the unsaturated group-containing compound (B).

Specifically, for example, the polyester-based resin (A) and the unsaturated group-containing compound (B) are placed in a solvent in the presence of a catalyst at a normal room temperature to 100 ° C., preferably 40 to 90 ° C. and usually 0.5 to 10 hours. A functional group capable of reacting with the acid anhydride group in the polyester resin (A) and the acid anhydride group in the unsaturated group-containing compound (B), preferably by mixing under the conditions of 1 to 5 hours. Can be reacted.
The catalyst is not particularly limited, but an amine-based catalyst is preferable, and triethylamine is particularly preferable because it easily volatilizes in the drying process.

The acid anhydride group is opened by the reaction of the acid anhydride group in the polyester resin (A) and the functional group capable of reacting with the acid anhydride group in the unsaturated group-containing compound (B), and the polyester is polyester. A carboxyl group can be added to the side chain of the based resin (A), and at the same time, the unsaturated group-containing compound (B) can be added to the polyester based resin (A). That is, an unsaturated group can be introduced into the polyester resin (A).

At this time, the molar ratio of the functional group capable of reacting with the acid anhydride group in the polyester resin (A) and the acid anhydride in the unsaturated group-containing compound (B) is determined from the viewpoint of reactivity of the polyester resin (1). The functional group capable of reacting with the acid anhydride in the unsaturated group-containing compound (B) is preferably 0.8 to 1.2 mol with respect to 1 mol of the acid anhydride group in A), preferably 0.9. It is more preferably ~ 1.1 mol, and particularly preferably 0.95 to 1.05.

The content of the unsaturated group of the polyester resin of the present embodiment is preferably 0.005 to 3 mmol / g, particularly 0.01 to 1 mmol / g, and particularly 0.03 to 0.8 mmol / g. Further, 0.05 to 0.4 mmol / g is preferable. If the content is too low, there is a tendency that sufficient adhesion cannot be obtained due to insufficient reaction points with the coating layer, and if the content is too high, the molecular weight of the polyester resin is lowered and the coating film strength is lowered, resulting in adhesion. Tends to decrease.

The content of unsaturated groups in the polyester resin of the present embodiment can be determined by the following formula (I).
Unsaturated group content (mmol / g) = (P1 _m × P1 _n ) / (P1 _mw × S1) ... Formula (I)
In the formula (I), P1 _m is the mass (mg) of the _{unsaturated group-containing compound, P1 n} is the number of unsaturated groups per molecule of the unsaturated group-containing compound, and P1 _mw is the molecular weight of the unsaturated group-containing compound (g / g /). mol) and S1 are the solid content mass (g) of the polyester-based resin having an unsaturated group.

Thus, the polyester resin of the present embodiment can be obtained.

The polyester resin of the present invention contains, if necessary, antioxidants such as hindered phenols, heat stabilizers, glass fibers, inorganic / organic fillers, colorants, flame retardants, softeners, and dispersants. , Wetting agents, emulsifiers, gelling agents, defoaming agents, other thermoplastic resins and the like can be blended to the extent that the effects of the present invention are not impaired.

[Primer composition]
By containing the polyester resin of the present invention, the primer composition of the present invention can be obtained. The primer composition of the present invention preferably further contains a cross-linking agent.

<Crosslinking agent>
The cross-linking agent used in the present invention may be any as long as it causes a cross-linking reaction with the carboxyl group in the polyester-based resin of the present invention. , Metallic compounds, aziridine compounds, hydrazine compounds, hydrazide compounds, melamine compounds and the like.

The isocyanate-based compound may be any compound containing at least two isocyanate groups as functional groups in the molecule. For example, "Aquanate 110" and "Aquanate 210" manufactured by Nippon Polyurethane Co., Ltd., Dai-ichi Kogyo Seiyakusho Co., Ltd. "Elastron BN-27", "Elastron BN-77" manufactured by Meisei Chemical Industry Co., Ltd. "Meicanate TP-10", "SU-268A", "Trixene aqua BI200" manufactured by Baxenden Chemical Limited, "Trixene" "Aqua BI220" and the like can be mentioned.

Above all, an aliphatic isocyanate compound or an alicyclic isocyanate compound is more preferable than an aromatic isocyanate compound in order to avoid yellowing due to ultraviolet rays.
Further, from the viewpoint of stability, the functional group block type is preferable, and "SU-268A", "Trixene aqua BI220" and the like are preferable.

Examples of the oxazoline-based compound include addition polymerizable 2-oxazoline (for example, 2-isopropenyl-2-oxazoline) having a substituent having an unsaturated carbon-carbon bond at the carbon position at the 2-position, and other unsaturated monos. Examples of commercially available products include copolymers with polymers, such as "Epocross WS-500", "Epocross WS-700", "Epocross K-2010E", and "Epocross K-2020E" manufactured by Nippon Catalyst. , "Epocross K-2030E" and the like.

Examples of the epoxy compound include bisphenol A / epichlorohydrin type epoxy resin and sorbitol polyglycidyl ether (for example, "Denacol EX-611", "Denacol EX-612" and "Denacol EX-614" manufactured by Nagase ChemteX Corporation. , "Denacol EX-614B", "Denacol EX-622", etc.), Polyglycerol polyglycidyl ether (for example, "Denacol EX-512", "Denacol EX-521", etc. manufactured by Nagase Chemtex), Pentaerythritol poly Glycyzyl ether (for example, "Denacol EX-411" manufactured by Nagase Chemtex), diglycerol polyglycidyl ether (for example, "Denacol EX-421" manufactured by Nagase Chemtex), glycerol polyglycidyl ether (for example, "Denacol EX-421" manufactured by Nagase Chemtex). "Denacol EX-313", "Denacol EX-314", etc. manufactured by Nagase Chemtex), Trimethylol Propanepolyglycidyl Ether (for example, "Denacol EX-321", etc. manufactured by Nagase Chemtex), Resolsinol diglycidyl ether (For example, "Denacol EX-201" manufactured by Nagase Chemtex Co., Ltd.), Neopentyl glycol diglycidyl ether (for example, "Denacol EX-211" manufactured by Nagase Chemtex Co., Ltd.), 1,6-hexanediol diglycidyl Ether (for example, "Denacol EX-212" manufactured by Nagase Chemtex), hydrogenated bisphenol A diglycidyl ether (for example, "Denacol EX-252" manufactured by Nagase Chemtex), ethylene glycol diglycidyl Ether (for example, "Denacol EX-810" and "Denacol EX-811" manufactured by Nagase Chemtex), diethylene glycol diglycidyl ether (for example, "Denacol EX-850" and "Denacol EX-" manufactured by Nagase Chemtex). 851 ", etc.), Polyethylene Glycol Diglycidyl Ether (for example," Denacol EX-821 "," Denacol EX-830 "," Denacol EX-832 "," Denacol EX-841 "," Denacol EX "manufactured by Nagase ChemteX. -861 "etc.), Propropylene glycol diglycidyl ether (for example," Denacol EX-911 "manufactured by Nagase Chemtex, etc.), Polypropylene glycol diglycidyl ether (for example," Denaco "manufactured by Nagase Chemtex, etc.) Le EX-941 ”,“ Denacol EX-920 ”,“ Denacol EX-931 ”and the like. Among them, the aqueous type is preferable, and the bifunctional and linear structure such as ethylene glycol diglycidyl ether and diethylene glycol diglycidyl ether is particularly suitable from the viewpoint of adhesion between the coating layer and the primer layer.

The carbodiimide-based compound may be any compound containing at least two or more carbodiimide groups as functional groups or cyanamide groups having a tautomeric relationship thereof in the molecule. For example, "Carbodilite V-" manufactured by Nisshinbo Chemical Co., Ltd. 02 "," Carbodilite V-02-L2 "," Carbodilite SV-02 "," Carbodilite V-04 "," Carbodilite V-10 "," Carbodilite E-03A "," Carbodilite E-02 "," Carbodilite E " -04 "and the like. Among them, those having an aromatic group such as a xylylene skeleton, a trilene skeleton, a diphenylmethane skeleton, and a tetramethylxylylene skeleton are preferable from the viewpoint of adhesion between the coating layer and the primer layer, and particularly "carbodilite V-04" and "carbodilite". "E-04" and the like are suitable.

Examples of the amine compound include hexamethylenediamine and triethanolamine.

Examples of the metal compound include metal alkoxides such as tetraethyl titanate, tetraethylzirconate, and aluminum isopropionate, and aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, zirconium, and the like. Examples thereof include acetylacetone and acetoacetic acid esters of polyvalent metals, metal chelate compounds of ethylenediamine tetraacetic acid coordination compounds, acetate-ammonium complex salts, ammonium-carbonate complex salts and the like.

The aziridine-based compound may contain at least two or more aziridine groups, and examples thereof include "Chemitite PZ-33" and "Chemitite DZ-22E" manufactured by Nippon Shokubai.

The hydrazine-based compound may contain at least two or more hydrazine groups, and examples thereof include hydrazine monohydrochloride, hydrazine dihydrochloride, hydrazine monobromic acid, and hydrazine carbonate.

Examples of the hydrazide compound include adipic acid dihydrazide, sebacic acid dihydrazide, dodecandiohydrazide, isophthalic acid dihydrazide, salicylic acid hydrazide and the like.

Examples of the melamine-based compound include hexamethoxymethylol melamine, Sanwa Chemical Co., Ltd.'s "Nicarac MW-30M", "Nicarac MW-30", "Nicarac MW-22", "Nicarac MS-11", and "Nicarac". Methylated melamine resins such as "MS-011", "Nicarac MX-730", "Nicalac MX-750", "Nicalac MX-706", "Nicalac MX-035", "Nicalac MX-45", "Nicalac MX-" Examples thereof include mixed etherified melamine resins such as "410".

As the cross-linking agent, only one kind selected from these may be used, or two or more kinds may be used in combination.

In the present invention, among the above, isocyanate-based compounds, oxazoline-based compounds, epoxy-based compounds, and carbodiimide-based compounds are preferable, and isocyanate-based compounds and carbodiimide-based compounds are particularly preferable, and carbodiimide-based compounds are particularly preferable, from the viewpoint of adhesion between the coating layer and the primer layer. The system compound is more preferable.

In particular, the thickness of the primer layer is preferably thin from the viewpoint of cost and transparency, but if the thickness is thin, the adhesion tends to decrease. Therefore, when forming a nano-order thin film by in-line coating, the above-mentioned preferable cross-linking is particularly preferable. The use of agents is particularly effective.

The content of the cross-linking agent can be appropriately selected depending on the amount of functional groups contained in the polyester-based resin of the present invention, the molecular weight of the polyester-based resin of the present invention, and the purpose of use, but the polyester-based resin of the present invention and the cross-linking agent can be appropriately selected. The mass ratio (mass of the polyester resin of the present invention / mass of the cross-linking agent) is preferably 99/1 to 30/70, particularly 95/5 to 40/60, particularly 90/10 to 50/50. Further, 80/20 to 60/40 is preferable.

If the content of the cross-linking agent is too high or too low, the adhesion and the heat resistance to moisture tend to decrease due to insufficient cross-linking.

When X in the structure (1) of the polyester resin of the present invention has an unsaturated group, the unsaturated group of the polyester resin having an unsaturated group in X in the structure (1) in the primer composition The content is preferably 0.003 to 1 mmol / g, particularly preferably 0.005 to 0.5 mmol / g, and further preferably 0.01 to 0.3 mmol / g.

If the content is too low, there is a tendency that sufficient adhesion cannot be obtained due to insufficient reaction points with the coating layer, and if the content is too high, the molecular weight of the polyester resin is lowered and the coating film strength is lowered, resulting in adhesion. Tends to decrease.

The content of unsaturated groups in the polyester resin in the primer composition can be determined by the following formula (II).
Unsaturated group content (mmol / g) = (P2 _m × P2 _n ) / (P2 _mw × S2) ... Equation (II)
In formula (II), P2 _m is the mass (mg) of the _{unsaturated group-containing compound, P2 n} is the number of unsaturated groups per molecule of the unsaturated group-containing compound, and P2 _mw is the molecular weight of the unsaturated group-containing compound (g / g /). mol) and S2 are the total solid content mass (g) of the primer composition.

In addition to the above components, the primer composition of the present invention contains, if necessary, antioxidants such as hindered phenols, heat stabilizers, glass fibers, inorganic / organic fillers, colorants, flame retardants, and softening agents. Agents, dispersants, wetting agents, emulsifiers, gelling agents, defoaming agents, other thermoplastic resins and the like can be blended to the extent that the effects of the present invention are not impaired.

The method for producing the primer composition of the present invention is not particularly limited, and for example, each component may be appropriately mixed using a stirring device.

[Aqueous liquid]
The aqueous solution of the present invention is obtained by dissolving or dispersing the polyester resin of the present invention or the primer composition of the present invention in an aqueous solvent. Hereinafter, dissolution or dispersion in an aqueous solvent is referred to as "water dissolution or water dispersion".

The aqueous solution of the present invention can be prepared by appropriately mixing the polyester-based resin of the present invention, the primer composition of the present invention, and an aqueous solvent. For example, (1) the polyester-based resin of the present invention and A method of mixing a cross-linking agent and then mixing an aqueous solvent to prepare an aqueous solution. (2) Each of the polyester resin and the cross-linking agent of the present invention is prepared as an aqueous solution with an aqueous solvent, and these are mixed to obtain an aqueous solution. Methods include (3) a method in which either the polyester resin or the cross-linking agent of the present invention is prepared as an aqueous solution with an aqueous solvent, and the remaining components are further mixed to form an aqueous solution, but the preparation is easy. The method (2) above is preferable.

Examples of the aqueous solvent include water or a mixture of water and an appropriate hydrophilic organic solvent. Examples of the hydrophilic organic solvent include ketones such as acetone and methyl ethyl ketone; alcohols such as methanol, ethanol and isopropyl alcohol; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monobutyl ether and ethylene glycol monotarsial butyl ether. Etc., which can be mixed with water. When a hydrophilic organic solvent is used, the ratio of the aqueous solution to the whole is appropriately set. For example, it can be set in the range of 30% by mass or less, but is not limited to this. Further, one kind selected from these aqueous solvents may be used, or two or more kinds may be used in combination.

When preparing the aqueous solution of the present invention, it is preferable to add a neutralizing agent in order to uniformly dissolve or disperse the aqueous solution in the aqueous medium, and the neutralizing agent is contained in the primer composition of the present invention. Any material can be used as long as it can neutralize the carboxyl group of the polyester resin and the cross-linking agent of the present invention.

Specifically, for example, metal hydroxides such as lithium hydroxide, potassium hydroxide, and sodium hydroxide; ethylamine, diethylamine, triethylamine, propylamine, isopropylamine, iminobispropylamine, 3-ethoxypropylamine, 3-. Organic amines such as diethylaminopropylamine, diethanolamine, triethanolamine, N, N-diethylethanolamine, N, N-dimethylethanolamine, aminoethanolamine, morpholin, N-methylmorpholin, N-ethylmorpholin; and ammonia and the like. Can be mentioned. One kind selected from these neutralizing agents may be used, or two or more kinds may be used in combination.

Among these neutralizing agents, those having a boiling point of 150 ° C. or lower are preferable in terms of water resistance of the obtained film, which is easily volatilized by drying. In particular, ammonia and triethylamine are preferable, and ammonia is particularly preferable because of its high versatility, low boiling point, and easy volatilization during drying.

In addition, a surfactant such as an anionic surfactant or a nonionic surfactant can be added to this aqueous solution, if necessary. By blending a surfactant, it is possible to improve the wettability to the base film when the aqueous liquid is applied to a base material such as a polyester film.

Any suitable surfactant can be used, for example, polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester, fatty acid metal soap, alkyl sulfate, alkyl sulfonate, etc. Examples thereof include alkyl sulfosuccinates and dodecylbenzene sulfonates. One kind selected from these surfactants may be used, or two or more kinds may be used together.
From the viewpoint of adhesion between the coating layer and the primer layer and water resistance of the primer layer, it is preferable not to add a surfactant.

Further, the aqueous solution of the present invention may further contain, for example, an antistatic agent, a filler, an ultraviolet absorber, a lubricant, a colorant and the like, if necessary.

The concentration of the solid content of the aqueous liquid of the present invention is appropriately adjusted so as to ensure good dispersibility of the polyester resin of the present invention, and is preferably 5 to 30% by mass, for example. At the time of coating, it is appropriately diluted to obtain a desired film thickness, and for example, the solid content concentration is adjusted to 1 to 15% by mass before use.

[Base film with primer layer]
By applying the above aqueous solution to the base film and heating and drying, a film (primer layer) formed by cross-linking the polyester resin of the present invention in the primer composition with a cross-linking agent is formed, and a primer layer is attached. A base film can be obtained.

Examples of the base film include polyester resins such as polyethylene naphthalate, polyethylene-2,6-naphthalate, polyethylene terephthalate, polybutylene terephthalate, and polyethylene terephthalate / isophthalate copolymer; polyethylene, polypropylene, polymethylpentene, and the like. Polyolefin-based resins; Polyfluorinated ethylene resins such as polyvinylfluoride, vinylidene polyvinylfluoride, and ethylene polyfluoride; polyamides such as nylon 6, nylon 6,6, etc .; polyvinyl chloride, polyvinyl chloride / vinyl acetate copolymer, ethylene- Vinyl acetate copolymers, ethylene-vinyl alcohol copolymers, vinyl polymers such as polyvinyl alcohol and vinylon; cellulose-based resins such as cellulose triacetate and cellophane; methyl polymethacrylate, ethyl polymethacrylate, ethyl polyacrylate, Acrylic resins such as butyl polyacrylate; monolayers or multilayers selected from synthetic resin films or sheets such as polystyrene, polycarbonate, polyarylate, and polyimide.
Among them, a polyester film is preferably used from the viewpoints of transparency, chemical resistance, heat resistance, mechanical strength, cost and the like.
The polyester-based film may be either an unstretched film or a stretched film, but it is preferable to use a stretched film, and it is particularly preferable to use a biaxially stretched film.

As a method for applying the aqueous liquid, a known general method can be used, and examples thereof include a method of applying a kiss coat, a reverse coat, a gravure coat, a die coat and the like on one side or both sides of the base film.

The thickness of the primer layer after heating and drying (after crosslinking) is preferably 0.01 to 2 μm, more preferably 0.02 to 0.5 μm, particularly 0.03 to 0.3 μm, particularly. It is preferably 0.05 to 0.15 μm. If the thickness is too thin, the adhesion tends to decrease, and if the thickness is too thick, the optical properties such as transparency and haze and the blocking resistance tend to decrease.

A laminated film or a prism sheet can be obtained by further providing a coating layer on the primer layer of the base film with a primer layer and using the coating layer as a hard coat layer or a prism layer.

Examples of the material forming the coating layer include acrylic resins, epoxy resins, urethane resins, and active energy ray-curable resin compositions generally used as coating materials. Among them, active energy ray-curable. The sex resin composition is preferable.

Specifically, the primer of the base film with a primer layer is coated by applying an active energy ray-curable resin composition on the primer layer of the base film with a primer layer and irradiating the primer layer with active energy rays to cure the primer. A laminated film having a hard coat layer obtained by curing the active energy ray-curable resin composition can be obtained on the layer.

The thickness of the hard coat layer is usually 0.5 to 15 μm, preferably 1 to 10 μm, and particularly preferably 2 to 7 μm.

[Prism sheet]
Further, a prism layer can be formed on the primer layer of the base film with a primer layer to obtain a prism sheet.

The prism layer is preferably a prism layer obtained by curing the active energy ray-curable resin composition, and particularly preferably a prism layer formed by curing the solvent-free active energy ray-curable resin composition. be.

As a method for forming the prism layer when the prism layer is a prism layer obtained by curing the active energy ray-curable resin composition, for example, an active energy ray-curable resin composition is introduced into a prism type to form a prism type. The active energy ray-curable resin composition is irradiated with the active energy ray-curable resin composition sandwiched between the primer layer side of the base film with the primer layer (particularly the polyester film) to cure the resin composition and remove the prism type. Thereby, a method of forming a prism layer formed by curing the active energy ray-curable resin composition on the base film can be mentioned.

The method for applying the active energy ray-curable resin composition is not particularly limited, and for example, spray, shower, dipping, roll, spin, curtain, flow, slit, die, gravure, comma, dispenser, etc. Wet coating methods such as screen printing, inkjet printing and the like can be mentioned.

As the active energy rays, for example, far ultraviolet rays, ultraviolet rays, near ultraviolet rays, rays such as infrared rays, electromagnetic waves such as X-rays and γ-rays, as well as electron beams, proton beams, neutron rays and the like can be used. Curing by ultraviolet irradiation is advantageous because of the availability of the device and the price.

As a method of curing by ultraviolet irradiation, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a chemical lamp, an electrodeless discharge lamp, an LED, etc. that emit light in the wavelength range of 150 to 450 nm are used. It suffices to irradiate about 30 to 3,000 mJ / cm ^2.
After irradiation with ultraviolet rays, heating can be performed as necessary to complete the curing.

The thickness of the prism layer is preferably 5 to 50 μm, particularly preferably 10 to 45 μm, further preferably 15 to 40 μm, and particularly preferably 20 to 35 μm.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. In the following, "part" and "%" are based on mass.
The method for measuring each physical property value of the polyester resin is as follows.

(1) Method for determining the content of unsaturated group The content of unsaturated group (mmol / g) was determined by the following formula (Ia).
The content of unsaturated groups (mmol / g) = P1 ' m / (P1' mw × S1 ') ··· formula (Ia)
Wherein (Ia), P1 _'m is PEGMA mass (mg), P1' _mw average molecular weight of PEGMA (g / mol) (calculated from its hydroxyl number), polyester having an unsaturated group S1 'is obtained The solid content mass (g) of the resin. The PEGMA means "polyethylene glycol monoacrylate used in the reaction".

(2) Method for measuring acid value The acid value (mgKOH / g) is determined by dissolving 1 g of a polyester resin in 30 g of a mixed solvent of toluene / methanol = 7/3 (volume ratio) and performing neutralization titration based on JIS K0070. rice field.
In the present invention, the acid value of the polyester resin is due to the content of the carboxyl group in the resin.

(3) Peak Top Molecular Weight and Weight Average Molecular Weight The peak top molecular weight and weight average molecular weight are measured by high performance liquid chromatography (manufactured by Toso Co., Ltd., “HLC-8320GPC”) on a column (TSKgel SuperMultipore HZ-M (exclusion limit molecular weight: 2 ×). 10 ^6, theoretical plates: 16,000 plates / the filler material: styrene - divinylbenzene copolymer, filler particle size: measured using two series of 4 [mu] m), was determined by standard polystyrene equivalent value of molecular weight.

[Manufacturing Example 1]
[Manufacturing of polyester resin (A1)]
In a reaction can equipped with a thermometer, a stirrer, a rectification tower, and a nitrogen introduction tube, 305.6 parts (1.839 mol) of isophthalic acid (IPA) as a polyvalent carboxylic acid component and diethylene glycol (DEG) 185 as a polyol component. 4 parts (1.747 mol), 28.7 parts (0.276 mol) of neopentyl glycol (NPG), and 0.3 part of tetrabutyl titanate as a catalyst were charged, and it took 90 minutes until the internal temperature reached 200 to 270 ° C. The temperature was raised and the esterification reaction was carried out at 270 ° C. for 3 hours.

Next, 533.8 parts of methyl ethyl ketone was added while lowering the internal temperature to 80 ° C., and when the resin was completely dissolved, 80.2 parts (0.368 mol) of pyromellitic acid anhydride (PMAn) was added, and triethylamine 2.7 as a catalyst. The addition reaction was carried out for 1.5 hours to obtain a 50% solid content solution of a polyester resin (A1) having an acid anhydride structure at the molecular end of the main chain. Table 1 shows the physical characteristics of the polyester resin (A1).

[Manufacturing Example 2]
[Manufacturing of polyester resin (A2)]
In a reaction can equipped with a thermometer, a stirrer, a rectification tower, and a nitrogen introduction tube, 343.5 parts (2.068 mol) of isophthalic acid (IPA) as a polyvalent carboxylic acid component and diethylene glycol (DEG) 175 as a polyol component. 5 parts (1.654 mol), 53.8 parts (0.517 mol) of neopentyl glycol (NPG), and 0.3 part of tetrabutyl titanate as a catalyst were charged, and it took 90 minutes until the internal temperature reached 200 to 270 ° C. The temperature was raised and the esterification reaction was carried out at 270 ° C. for 3 hours.

Next, 525.6 parts of methyl ethyl ketone was added while lowering the internal temperature to 80 ° C., and when the resin was completely dissolved, 27.1 parts (0.125 mol) of pyromellitic acid anhydride (PMAn) was added, and triethylamine 2.7 as a catalyst. The addition reaction was carried out for 1.5 hours to obtain a 50% solid content solution of a polyester resin (A2) having an acid anhydride structure at the molecular end of the main chain. Table 1 shows the physical characteristics of the polyester resin (A2).

[Example 1]
[Manufacturing of Polyester Resin 1 Having Structure (1)]
200 parts of polyester resin (A1) solution having a solid content of 50% obtained in Production Example 1, 35.8 parts of polyethylene glycol monoacrylate (PEGMA-1, average molecular weight calculated from hydroxyl value: 540), 0 triethylamine as a catalyst .7 parts were charged into a reactor and an addition reaction was carried out at 80 ° C. for 3 hours to obtain a 58% solution of polyester resin 1 having an acryloyl group at the molecular end of the main chain. Table 1 shows the physical characteristics of the polyester resin 1.

[Preparation of polyester resin 1 aqueous dispersion]
34.5 parts of a polyester resin 1 solution having a solid content of 58%, 63.5 parts of deionized water, and 2 parts of 25% ammonia water obtained above were charged into a reactor and dispersed in water while stirring at room temperature to solidify. A polyester resin 1 aqueous solution (aqueous dispersion) having a concentration of 20% was prepared.

[Preparation of primer composition]
As shown in Table 2, the polyester-based resin 1 aqueous liquid (aqueous dispersion) obtained above and the carbodiimide-based cross-linking agent "Carbodilite V-04" (manufactured by Nisshinbo Chemical Co., Ltd.) are mixed with a polyester-based resin having a solid content mass ratio. A primer composition was prepared by mixing the mixture so as to have a ratio of 1: 70.0 and a carbodiimide-based cross-linking agent: 30.0, and stirring at room temperature for 1 hour.

[Example 2]

[Manufacturing of polyester resin 2 having structure (1)]
200 parts of polyester resin (A1) solution having a solid content of 50% obtained in Production Example 1, 23.4 parts of polyethylene glycol monoacrylate (PEGMA-2, average molecular weight calculated from hydroxyl value: 350), 0 triethylamine as a catalyst .6 parts were charged into a reactor and an addition reaction was carried out at 80 ° C. for 3 hours to obtain a 55% solution of polyester resin 2 having an acryloyl group at the molecular end of the main chain. Table 1 shows the physical characteristics of the polyester resin 2.

[Preparation of polyester resin 2 aqueous dispersion]
36.4 parts of the polyester resin 2 solution having a solid content of 55%, 61.6 parts of deionized water, and 2 parts of 25% ammonia water obtained above were charged into a reactor and dispersed in water while stirring at room temperature to solidify. A polyester resin 2 aqueous solution (aqueous dispersion) having a component concentration of 20% was prepared.

[Preparation of primer composition]
As shown in Table 2, the polyester-based resin 2 aqueous liquid (aqueous dispersion) obtained above and the carbodiimide-based cross-linking agent "Carbodilite V-04" (manufactured by Nisshinbo Chemical Co., Ltd.) are mixed with a polyester-based resin having a solid content mass ratio. A primer composition was prepared by mixing the mixture so as to have a ratio of 2: 70.0 and a carbodiimide-based cross-linking agent: 30.0, and stirring at room temperature for 1 hour.

[Example 3]
[Manufacturing of Polyester Resin 3 Having Structure (1)]
200 parts of polyester resin (A2) solution having a solid content of 50% obtained in Production Example 2, 4.3 parts of polyethylene glycol monoacrylate (PEGMA-1, average molecular weight calculated from hydroxyl value: 540), 0 triethylamine as a catalyst. .7 parts were charged into a reactor and an addition reaction was carried out at 80 ° C. for 3 hours to obtain a 51% solution of a polyester resin 3 having an acryloyl group at the molecular end of the main chain. Table 1 shows the physical characteristics of the polyester resin 3.

[Preparation of polyester resin 3 aqueous dispersion]
39.3 parts of the polyester resin 3 solution having a solid content of 51%, 59.9 parts of deionized water, and 0.8 part of 25% ammonia water obtained above were charged in a reactor and dispersed in water while stirring at room temperature. , A polyester resin tri-aqueous solution (aqueous dispersion) having a solid content concentration of 20% was prepared.

[Preparation of primer composition]
As shown in Table 2, the polyester-based resin 3 aqueous liquid (aqueous dispersion) obtained above and the carbodiimide-based cross-linking agent “Carbodiimide V-04” (manufactured by Nisshinbo Chemical Co., Ltd.) are mixed with a polyester-based resin having a solid content mass ratio. A primer composition was prepared by mixing the mixture so as to have a ratio of 3: 70.0 and a carbodiimide-based cross-linking agent: 30.0, and stirring at room temperature for 1 hour.

[Comparative Example 1]
[Preparation of polyester resin (A1) aqueous dispersion]
40 parts of a polyester resin (A1) solution having a solid content of 50%, 56 parts of deionized water, and 4 parts of 25% ammonia water obtained in Production Example 1 were charged into a reactor and dispersed in water while stirring at room temperature to solidify. A polyester resin (A1) aqueous solution (aqueous dispersion) having a concentration of 20% was prepared.

[Preparation of primer composition]
As shown in Table 2, the polyester-based resin (A1) aqueous solution (aqueous dispersion) obtained above and the carbodiimide-based cross-linking agent "Carbodilite V-04" (manufactured by Nisshinbo Chemical Co., Ltd.) have a solid content mass ratio of polyester. A primer composition was prepared by mixing the system resin (A1) so as to be 70.0 and the carbodiimide-based cross-linking agent: 30.0 and stirring at room temperature for 1 hour.

[Comparative Example 2]
[Preparation of primer composition]
As shown in Table 2, the polyester resin (A1) aqueous solution (aqueous dispersion) obtained above, the carbodiimide-based cross-linking agent “Carbodiimide V-04” (manufactured by Nisshinbo Chemical Co., Ltd.), and PEGMA-1 have solid contents. The primer composition was prepared by mixing the mixture so that the mass ratio was polyester resin (A1): 51.5, carbodiimide-based cross-linking agent: 30.0, and PEGMA-1: 18.5, and stirring at room temperature for 1 hour. Prepared.

[Comparative Example 3]
[Preparation of primer composition]
As shown in Table 2, the polyester resin (A1) aqueous solution (aqueous dispersion) obtained above, the carbodiimide-based cross-linking agent “Carbodiimide V-04” (manufactured by Nisshinbo Chemical Co., Ltd.), and PEGMA-2 have solid contents. The primer composition was prepared by mixing the mixture so that the mass ratio was polyester resin (A1): 56.7, carbodiimide-based cross-linking agent: 30.0, and PEGMA-1: 13.3, and stirring at room temperature for 1 hour. Prepared.

[Adhesion evaluation]
Each primer composition prepared in the above Examples and Comparative Examples was diluted with deionized water so that the solid content was 3% to prepare a coating solution of the primer composition. The prepared coating liquid was applied to a PET film "Lumirror T60" (manufactured by Toray Industries, Inc., thickness 100 μm) on a bar coater No. A primer layer was formed by applying at 6 and drying at 150 ° C. for 3 minutes.

Next, a solvent-free ultraviolet curable resin composition "Sunrad A" (manufactured by Sanyo Chemical Industries, Ltd.) for forming a prism layer was applied onto the primer layer using an applicator, and subsequently 13 cm above the coated surface. ^{The ultraviolet curable resin composition was cured by irradiating ultraviolet rays at 400 mJ / cm 2} using a high-pressure mercury lamp having an irradiation intensity of 80 W / cm set in the above, and a resin layer having a thickness of 25 μm was formed.

^{100 pieces of 1 mm 2} crosscuts were put into the ultraviolet curable resin layer thus formed, cellophane tape (registered trademark) manufactured by Nichiban Co., Ltd. was attached onto the cloth, and the tape was rubbed with a plastic eraser to sufficiently adhere to the tape. After that, it was rapidly peeled off in the 90 ° direction, the degree of peeling of the UV-curable resin layer, that is, the number of remaining UV-curable resin layers per 100 crosscuts was counted, and the adhesion was evaluated according to the following criteria.

(Evaluation criteria) (remaining number / measured number)
⊚: 100/100
◯: 80/100 or more, 99/100 or less Δ: 51/100 or more, 79/100 or less ×: 50/100 or less

From the results in Table 2, since the primer layer formed from the primer compositions of Examples 1 to 3 contains the polyester resin having the structure (1), it adheres to both the base film and the coating layer. It turned out to be excellent in sex.

On the other hand, the polyester resin used in Comparative Example 1 did not have the structure (1), and therefore had poor adhesion. Further, in Comparative Examples 2 and 3, although the compound having the structure (1) was contained, the structure (1) was not bonded to the polyester resin, so that the effect of the structure (1) was not exhibited. The adhesion was inferior.

The primer composition obtained from the polyester resin of the present invention can be suitably used as a primer for a base film. Further, the obtained base film with a primer layer has excellent adhesion to a coating layer obtained by curing the active energy ray-curable resin composition, and is, for example, a label sheet, a printing sheet, a hard coat film, or the like. It is useful as a sheet such as a prism sheet in which a coating layer is provided on a film, and is particularly useful as a prism sheet.

Claims (13)

Having a carboxyl group in the side chain of the main chain, have a structure represented by the following formula (1) in at least one location of the at least one molecular end of the side chain and the main chain of the main chain,
A polyester resin having an unsaturated group content of 0.005 to 3 mmol / g.

(In the formula (1), R represents an alkylene group having 1 to 5 carbon atoms, X represents a ( meth) acryloyl group, and n represents an integer of 1 to 20.) The polyester-based resin according to claim 1, wherein the content of the structure represented by the formula (1) is 1 to 30% by mass. The polyester-based resin according to claim 1 or 2 , wherein the acid value is 1.5 to 150 mgKOH / g. The polyester-based resin according to any one of claims 1 to 3 , wherein the weight average molecular weight is 5,000 to 100,000. An aqueous liquid comprising the polyester resin according to any one of claims 1 to 4 dissolved or dispersed in an aqueous solvent. A primer composition comprising the polyester-based resin according to any one of claims 1 to 4. The primer composition according to claim 6 , further comprising a cross-linking agent. The primer composition according to claim 7 , wherein the cross-linking agent is at least one compound selected from the group consisting of an isocyanate-based compound and a carbodiimide-based compound. The primer composition according to claim 7 or 8 , wherein the content ratio of the polyester resin to the cross-linking agent is 99/1 to 30/70 as the mass of the polyester resin / the mass of the cross-linking agent. .. An aqueous liquid comprising the primer composition according to any one of claims 6 to 9 dissolved or dispersed in an aqueous solvent. A base film with a primer layer, which comprises a primer layer comprising the primer composition according to any one of claims 6 to 9 on the base film. A prism sheet comprising a prism layer on the primer layer of the substrate film with a primer layer according to claim 11. The prism sheet according to claim 12 , wherein the prism layer is a cured product of a solvent-free active energy ray-curable resin composition.